Surface watercraft



April 26, 1966 W, A, GRMG 3,247,821

' SURFACE WATERCRAFT Filed Feb. 14, 1964 INVENTOR. 114410511708 :4. 1

United States Patent 3,247,821 SURFACE WATERCRAFT Waldemar A. Graig, 729 Grand Ave., Dayton, Ohio Filed Feb. 14, 1964, Ser. No. 344,977 9 Claims. (Cl. 11466.5)

This is a continuation-in-part of my copending appli cation for Watercraft, Serial No. 801,793, filed March 25, 1959, now Patent No. 3,124,096.

This invention pertains to watercraft which are supported, even if only partially, by dynamic lift forces generated by speed. Safety and maneuverability of this type of craft requires that they be steeply banked when engaged in tight turns. The invention satisfies this requirement. More specifically, the invention relates to the lateral stabilization and banking control of the watercraft, or at least their lift elements, i.e., devices which produce the dynamic sustentation. In the interest of clarity, the specification and claims make no distinction between banking the entire craft and the lift elements, since in most instances, the distinction is nominal: really the craft and the lift elements bank together. However, the prime concern is with the bank of the lift elements. The terms bank, tilt, etc., and their derivatives will be used interchangeably.

The purpose of the invention is to achieve: (a) a controlled banking by an operator (human or otherwise) who induces a rolling moment and the crafts rotation toward the desired bank angle; and (b), stabilization of the craft at that angle by means which do not require manipulation of the controls by the operator i.e., achieve automatic stabilization.

To achieve this objective-an advancement over the conventional steering methodsthe invention dependson means mounted at a vertical distance from the crafts center of gravity, and so arranged as to produce forces that Will act sideways and thus create rolling moments in response to two signals (inputs, directives)one issued by the crafts operator who selects the bank angle, the other issued by a mechanism (the term is used here in its broadest sense) which senses the banking condition, and thus reacts to upsetting rolling moments and maintains the craft at the selected bank angle. Arrangements are provided to mix or integrate the two directives, so that the means producing the lateral force and the associated rolling moment are activated by the combination (or resultant) of both control inputs one being a control input, the other a stabilization input.

The objectives set forth above, and other improvements achieved by the invention will become still more apparent from a reading of the description, and an examination of the drawings which are merely illustrative examples, in which:

FIG. 1 is a side view of a watercraft provided with an aerodynamic device producing controllable bank regulating forces and moments.

FIG. 2 is a schematic representation of the control system associated with the aerodynamic device of FIGURE 1.

FIG. 3 is a side view showing a portion of an aerodynamic control, alternate to that shown in FIGURE 1.

FIG. 4 shows the rear view in banked position of a watercraft equipped with floats that can be used as sensing devices in the production of one of the control inputs activating the aerodynamic control of FIGURE 1. It does not show the aerodynamic device itself, the constitution of which is disclosed by FIGURE 1.

FIG. 5 is a cross sectional side View of a bank regulating device alternate to that shown in FIGURE 1.

Details not essential to the understanding of the invention are not shown in the figures.

Referring to FIGURES 1, 2 and 4, the watercraft is with respect to the hull.

represented by hull 1, to which two lateral floats 2 and 3 are attached. The two floats are interconnected by means including a transverse beam 74, which is rotatably mounted on hull 1. The water exercises pressure during the run against the hydroplaning hull and floats, and thus provides dynamic sustentation.

A vertical aerodynamic fin 112 is erected above the crafts center of gravity on a mast 110. The fin is of a conventional free-floating design- (as used in aircraft for purposes unrelated to this invention). It is a plane of airfoil section rotatably mounted on a substantially vertical axis 114, which is in front of the fins center of pressure. For control purposes, a control tab 114' is hinged to the fin about an axis substantially parallel to the trailing edge. The tab can be included into the trailing edge of the fin, as shown, blending as it were into the fins contour when it is in neutral position; or it can be a small surface hinged to a beamlet extending rearward from the fin. Thus, as long as tab 114' is not deflected and remains co-planar with fin 112, the latter weathercocks into the relative wind and produces no substantial aerodynamic force, only drag (both, fin and tab are in this embodiment of symmetrical sections). When deflected, the tab 114' rotates the fin, which assumes a lifting angle of attack and produces a sideways acting lift force and consequently, a rolling moment. In a craft propelled by an airscrew, fan, jet, etc., it is preferable that the fin be placed in the downwash. The latter is deflected by the operation of the fin.

The control of this arrangement is achieved as follows. Referring to FIGURE 2, a differential gear 116 is rotatively mounted in the hull 1, in bearings 117. Of the several rotative elements of the differential gear 116, the following three accomplish a special function in the control procedure: bevel gears 120, 122 and cage 118. The gear 122 is fixedly mounted on shaft 20, which is journaled in a bearing transversing the sternpost (not shown). At its opposite end the shaft 20 is solidly joined to a transverse beam 74, carrying on both ends suitable extensions 68 and 70, with two floats 2 and 3 (FIG. 4). The detailed kinematics of the connections shown, explained in my co-pending applications for Watercraft, Serial No. 344,943, filed on February 14, 1964, are not pertinent to the present invention. All that matters here is that the floats are pressed against the water, by the weight of the craft, but that the hydrodynamic forces sustain them on the surface, so that the beam 74 is always maintained in a substantially horizontal position, even when the hull 1 is banked. Consequently, the gear 122, rigidly locked as it is with beam 74, does not actually rotate with respect to earthcoordinates, but it can rotate relative to hull 1. The cage 118 of the differential 116 is coupled by links, cables, or any other suitable means with thecontrol tab 114'. This coupling is represented by the dashed line connecting the cage 118 and the tab 114. When a rolling moment causes the hull 1 to bank, the gear 122 rotates Assuming that the gear 120 is held in position, the cage 118 follows the gear 122 and rotates by half its angle, thereby deflecting tab 114 and hence, fin 112. Thus, the fin 112 produces a lift force and a stabilizing rolling moment.

On the other hand, to induce a bank, the operator ro-- tates the gear 120. This too deflects the cage 118, the tab 114 and the fin 112, and produces a rolling moment. As the craft responds and banks, the gear 122 enters into action, due to its rotation relative to the hull 1. (The operation of the control system is based on its kinematics relative to the hull, not the ground.) Thus, gear 122, rotating as it does in a direction opposite to the deflection of gear 120, slows down and reverses the rotation of cage 118. Gradually, cage 118, tab 114' and fin 112 revert Patented Apr. 26, 1 966 to neutral position-and the rolling moment induced by the Operator is reduced to zero. This occurs when the gears 120 and 122 find themselves deflected by symmetric (i.e., equal but opposite) angles. At this pointat a bank angle strictly related to the angular deflection of the gears initiated by the operatorthe static stability of the craft is restored, since any deviation from the banking angle brings about a stabilizing rolling moment.

The angular deflection of cage 118 is known to be equal to the semi-sum of the deflections of gears 120 and 122. Hence, the control output (signal) of the differential, as tnansmitted Ito fin 112, results from the integration of the two inputs received by the gears.

The horizontal beam 74 is only one of the means which may be employed to activate pinion 122. For example, this pinion could be stabilized gyroscopically; or, it could be made responsive not just to attitude sensing devices, but to devices which, in addition, react to roll velocities, or accelerations, or both. Some of the other variations that may have merit, depending on circumstances, are these: the oscillations of the beam 74 engendered by the Waves can be reduced by establishing shock absorbers on the legs 68 and 70, or in some other convenient location; and by introducing dampers in the transmission between gear 122 and the sensing device, e.g., floats 2 and 3 and beam 74 (in the case of FIGURE 2), or between the cage 118, and fin 112, various effects can be obtained which affect the dynamics of the operation.

The differential 116 itself is only an example of a signal integrating or mixing device that could be suitably used in conjunction with fin 112. One alternate arrangement is shown in FIG. 3. The mixing occurs here on the fin itself, without an integrating device being interposed between the means which produce the inputs, and the means which operate fin 112. For that purpose the fin 112 is provided with two independent control tabs 114 and 115. The tab 114 is activated directly by the operators controls, while tab 115 is operated from shaft 20, which is activated by beam 74, or from any other suitable sensor. Thus, the two tabs operate jointly the fin 112. Their control signals add algebraically.

FIGURE 5 shows an alternate aerodynamic device, which, like the fin 112, is located above the center of gravity. The device comprises vertical vanes 10, rotationally mounted about a vertical axis AA in a shroud 12, which also contains the crafts propulsor, such as, for example, a fan or propeller 14. The means driving the propeller are not shown. Due to the high velocity of the airstream in which they operate, the vanes are practically unaffected by the outside wind. Hence, they are not necessarily of the free floating type. They are directly connectedby mechanical linkage for exampleto the cage 118 of the differential, such as shown on FIGURE 2, or its substitutes. The deflection of the vanes deflects the slipstream, and creates a side force, like that produced by the fin 114 of FIGURE 1. The causes for the production of side forces are not exactly the same; but the deflections of fin 112 and vane 10 are comparable in their effects. Being responsive to the rotations of cage 118, the vanes 10 integrate two control inputs, as established in the discussion of FIGURE 2. The transmission operated by the cage is represented by its terminal link-the horn 16 attached to the spindle 18 of the vane 10.

When operated in cross-wind certain components of the Watercraft produce side forces, hence rolling moments. These moments are, of course, corrected by the operation of the device. However, the bank is thereby not completely reduced, though the residual tilt can be easily trimmed out by the operator.

By the same token, an aerodynamic fin like that of FIGURE 1 but differently controlled, could be designed with disregard of the effects of the cross wind. Instead of being of the free-floating, tab operated, type, the fin 114' could be directly linked to the control mechanism,- or be a fixed stabilizer provided with a hinged rudder. Thus,

the free floating feature of fin 114' as shown, is offered as a desirable refinement rather than an unqualified requirement.

The lift-force producing means of the invention are not limited to aerodynamic surfaces, as shown in the embodiments of FIGURES 1 and 5. Instead, other embodiments could make use of controllable autorotative, or power driven rotors, Magnus cylinders, jets, etc.

Other variations which do not affect significantly the stabilization system of FIGURE 1, but which could alter considerably the water-crafts configuration, are as follows: waterskis or surface piercing hydrofoils can be substituted for the floats 2 and 3 of FIGURES 1 and 2. Instead of being arranged at the stern, the tilt sensing device of FIGURES 1 and 2 can be moved forward, as far as desired, or even placed in front of the bow. The hull can be supported by hydrofoils, or airfoils, or any other dynamic lifting devices, instead of being of the hydroplaning type, as shown.

Although the invention has been described and illustrated with particular reference being made to the embodiments shown in the drawings, it will be readily understood that many modifications can be made without departing from the spirit and scope of the invention.

What I claim is:

1. A surface watercraft steerable substantially by regulation of its bank, said watercraft including: lifting elements to produce at speed dynamic support forces; steering means movable in either direction from a neutral position to produce a control input of a sign and magnitude corresponding to the shift of the steering means from its neutral position; means sensing the banking conditions of the watercraft to produce an automatically acting stabilization input of a sign and magnitude substantially corresponding to the banking condition of the watercraft; operable rolling moment producing means disposed at a vertical distance from the center of gravity of the watercraft, to produce sideways acting forces and the associated rolling moment of a sign and magnitude corresponding to the resultant of the control input and stabilization input; means to operate the rolling moment producing means in response to the control input and the stabilization input; said rolling moment producing means causing the watercraft to assume an angle of bank substantially determined by the control input and to automatically stabilize itself at that angle under the action of the stabilization input.

2. The watercraft of claim 1 wherein said rolling moment producing means includes at least one aerodynamic surface positioned in the relative wind resulting from the crafts motion and the movement of the ambient air and arranged to develop controllable aerodynamic forces.

3. The watercraft of claim 2 wherein said aerodynamic surface includes a free floating vertical fin of airfoil section rotatively mounted on a substantially vertical axis and means to deflect said fin into an aerodynamic lift producing attitude. I

4. The watercraft of claim 3 wherein said fin deflecting means includes at least one control tab hinged to said fin, and said fin is rotatively mounted on a substantially vertical axis established in front of said fins center of pressure, the activation of said control tab causing deflection of said fin to assume a lifting angle of attack.

5. The watercraft of claim 4 wherein said fin is provided with two control tabs, one of said tabs responsive to said means sensing the banking condition, the other of said tabs responsive to said steering means.

6. The watercraft of claim 1 wherein said means to operate said rolling moment producing means includes integrating means to receive two inputs with one from said steering means and the other from said banking condition sensing means, and to integrate said two inputs into a resultant operating control output.

7. The watercraft of claim 6 wherein said integrating means comprises a differential gear including two rotatively mounted elements, each positioned by a distinct control inout, and a third rotatively mounted element whose position is determined by the position'of the two rotary elements receiving control inputs, said third element producing the resultant control output.

8. The watercraft of claim 1 wherein said banking condition sensing means includes laterally arranged hydroplaning surfaces rotatively mounted on said watercraft.

9. The Watercraft of claim 1 including propulsive means creating an airflow directed rearwardly, wherein said rolltively mounted about a substantially vertical axis whereby activations of said vanes cause deflections of said airflow toward the side, the deflections of said airflow producing side forces.

References (liked by the Examiner UNITED STATES PATENTS 2,858,788 11/1958 Lyman 114-39 FOREIGN PATENTS 198,649 v 5/1924 Great Britain.

MILTON BUCHLER, Primary Examiner.

FERGUS S. MIDDLETON, Examiner. 

1. A SURFACE WATERCRAFT SUBSTANTIALLY BY REGULATION OF ITS BANK, SAID WATERCRAFT INCLUDING: LIFTING ELEMENTS TO PRODUCE AT SPEED DYNAMIC SUPPORT FORCES; STEERING MEANS MOVABLE IN EITHER DIRECTION FROM A NEUTRAL POSITION TO PRODUCE A CONTROL INPUT OF A SIGN AND MAGNITUDE CORRESPONDING TO THE SHIFT OF THE STEERING MEANS FROM ITS NEUTRAL POSITION; MEANS SENSING THE BANKING CONDITIONS OF THE WATERCRAFT TO PRODUCE AN AUTOMATICALLY ACTING STABILIZATION INPUT OF A SIGN AND MAGNITUDE SUBSTANTIALLY CORRESPONDING TO THE BANKING CONDITION OF THE WATERCRAFT; OPERABLE ROLLING MOMENT PRODUCING MEANS DISPOSED AT A VERTICAL DISTANCE FROM THE CENTER OF GRAVITY OF THE WATERCRAFT, TO PRODUCE SIDEWAYS ACTING FROCES AND THE ASSOCIATED ROLLING MOVEMENT OF A SIGN AND MAGNITUDE CORRESPONDING TO THE RESULTANT OF THE CONTROL INPUT AND STABILIZING INPUT; MEANS TO OPERATE THE ROLLING MOMENT PRODUCING MEANS IN RESPONSE TO THE CONTROL INPUT AND THE STABILIZATION INPUT; SAID ROLLING MOMENT PRODUCING MEANS CAUSING THE WATERCRAFT TO ASSUME AN ANGLE OF BANK SUBSTANTIALLY DETERMINED BY THE CONTROL INPUT AND TO AUTOMATICALLY STABILIZE ITSELF AT THAT ANGLE UNDER THE ACTION OF THE STABILIZATION INPUT. 